The noise generated by subsonic jet nozzles, commonly encountered in civilian aircraft, is rather significant and propagates in both the upstream and downstream directions due to large-scale and fine-scale turbulence ...The noise generated by subsonic jet nozzles, commonly encountered in civilian aircraft, is rather significant and propagates in both the upstream and downstream directions due to large-scale and fine-scale turbulence structures. In this paper, a distinctive inner wall treatment strategy, denoted as the Azimuthally-distributed Wavy Inner Wall (AWIW), is proposed, which is aimed at mitigating jet noise. Within this strategy, a circumferentially dispersed treatment wall characterized by a minute wavy pattern is substituted for the smooth inner wall in proximity to the nozzle outlet. To assess the effectiveness of the AWIW treatment, we conducted numerical simulations. The unsteady flow field and far-field noise were predicted by employing Large Eddy Simulations (LES) coupled with the Ffowcs Williams and Hawkings (FW-H) integration method. To gain a comprehensive understanding of the mechanism underlying the noise reduction facilitated by the AWIW treatment, it examined physical parameters such as the Lighthill source acoustic source term, the turbulent kinetic energy acoustic source term, and the shear layer instability. The results reveal that the AWIW treatment expedites the instability within the shear layer of the jet, leading to an early disruption of the jet shear layer, and consequently turbulent structures in varying sizes are generated downstream. This process effectively regulates the generation and emission of jet noise. By controlling the minor scale turbulence through the AWIW treatment, the mid- and high-frequency noise within the distant field can be significantly reduced. In the context of the flow field, the introduction of AWIW also leads to a decrease in drag on the inner wall surface of the jet, thereby improving the overall aerodynamic performance of the nozzle. Considering these attributes, the AWIW strategy emerges as a viable technique for the reduction of jet noise.展开更多
This article reviews Fuqing ZHANG’s contributions to mesoscale atmospheric science,from research to mentoring to academic service,over his 20-year career.His fundamental scientific contributions on predictability,dat...This article reviews Fuqing ZHANG’s contributions to mesoscale atmospheric science,from research to mentoring to academic service,over his 20-year career.His fundamental scientific contributions on predictability,data assimilation,and dynamics of high impact weather,especially gravity waves and tropical cyclones,are highlighted.His extremely generous efforts to efficiently transmit to the community new scientific knowledge and ideas through mentoring,interacting,workshop organizing,and reviewing are summarized.Special appreciation is given to his tremendous contributions to the development of mesoscale meteorology in China and the education of Chinese graduate students and young scientists.展开更多
1.Tribute to Alfred Krner and Guowei Zhang This special issue of Geoscience Frontiers（GSF）is a tribute vol-ume honoring the life and career of two world-renowned scientists,Professor Alfred Kroner and Academician Gu...1.Tribute to Alfred Krner and Guowei Zhang This special issue of Geoscience Frontiers（GSF）is a tribute vol-ume honoring the life and career of two world-renowned scientists,Professor Alfred Kroner and Academician Guowei Zhang.Weassemble here a set of research papers related to continental growth in Central Asia,展开更多
Tangya Tribute Rice is a famous and special product in Shandong Province,and it was awarded the National Geographical Indication Certificate trademark in 2011.This paper elaborated the specific production area,unique ...Tangya Tribute Rice is a famous and special product in Shandong Province,and it was awarded the National Geographical Indication Certificate trademark in 2011.This paper elaborated the specific production area,unique production environment,rich cultural history and unique product quality of Tangya Tribute Rice.In addition,from the aspects of choice of origin,variety selection,production management,timely harvesting and processing,it summarized the unique production methods of Tangya Tribute Rice.Besides,it discussed its development prospects,in order to maintain the brand quality of Tangya Tribute Rice to the greatest extent,and further improve the brand awareness and market competitiveness of Tangya Tribute Rice in the domestic and international markets.展开更多
It is commonly believed that most European clocks that reached China before the nineteenth century were sent to the emperor as diplomatic presents from European rulers,or were given to Chinese officials by European me...It is commonly believed that most European clocks that reached China before the nineteenth century were sent to the emperor as diplomatic presents from European rulers,or were given to Chinese officials by European merchants in attempts to improve trading conditions.Although such presents had been given in earlier times,British records show that,by the eighteenth century when the export of clocks to China reached its height,most clocks,including the finest,reached China as private trade goods.Once in Canton(Guangzhou),the best clocks were bought by local Chinese officials for inclusion in their annual tribute to the emperor and senior members of the government in Beijing,where many of these clocks survive in the former imperial collection.展开更多
In her article Chika Ezeanya reckons that it is an insult to the AU and to every African that a building as symbolic as the AU headquarters （HQ） is designed, built and maintained by a foreign country [China].
Yongle Palace stands as a testament to ancient artistic mastery and religious devotion.lts mid-20th-century relocation highlights China's extraordinary efforts in cultural heritage preservation.
Nanoemulsions(NEs)loaded with Tribute citrus essential oil(EO)were prepared using Tween-80.Five different concentrations(0,1,3,5,and 7%)were then incorporated into a gelatin base.The droplet size,PDI,and zeta potentia...Nanoemulsions(NEs)loaded with Tribute citrus essential oil(EO)were prepared using Tween-80.Five different concentrations(0,1,3,5,and 7%)were then incorporated into a gelatin base.The droplet size,PDI,and zeta potential of the NE after EO loading were found to be 241.4 nm,0.288,and-21.8 mV,respectively.The relationship between the NE and gelatin was examined by measuring the gelation behavior,water mobility,and gelatin structure.As the NE concentration increased,gel properties such as strength,hardness,springiness,adhesiveness,cohesiveness,gumminess,chewiness,and kgel declined.Gelling and melting temperatures were higher after the addition of varying amounts of NE compared with the control.Hydrogen bonding between NEs and gelatin interfered with the formation of a triple helix,as shown by multi-spectroscopic techniques including Fourier-transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD).Atomic force microscopy(AFM)revealed that higher NE contents resulted in greater aggregation in the gelatin.These results provide insight into the use of gelatin in EO delivery and describe the basic interaction between EO and gelatin and the resultant gelation behavior in the delivery system.展开更多
In this paper,I trace the post-war Japanese genealogy of studies on China's tribute system(imperial China's relatively tolerant approach to its foreign relations)in relation to the English-language work of his...In this paper,I trace the post-war Japanese genealogy of studies on China's tribute system(imperial China's relatively tolerant approach to its foreign relations)in relation to the English-language work of historian John King Fairbank(1907-91).I emphasize that,together with the sporadic Chinese studies into China's tribute system prior to the 1950s,it was the post-war research of Japanese historians that inspired Fairbank,who,in turn,further stimulated critical debates on the topic in Japan.I first concentrate on post-war Japanese debates concerning an"East Asian world order"based on a"system of investiture/tribute."This notion,developed by the Japanese historian Nishijima Sadao in 1962,precisely corresponds to Fairbank's 1941 understanding of the"tribute system"or"Confucian world-order,"but contrasts with Fairbank's later,controversial understanding of a"Chinese world order"as proposed in 1968.In the second part of this paper,I introduce Japanese historian Hamashita Takeshi's 1980s and 1990s arguments on the"tribute trade system"as representative of the younger generation within this genealogy,contrasting it with the work of Immanuel Wallerstein and Andre Gunder Frank.In the third part,Ⅰlocate this Japanese genealogy within the wider historical context of post-war Japanese intellectual cultural politics.This means that I examine Japanese historians'arguments both from the angle of historiography and from the perspective of post-war Japanese intellectual history.展开更多
David Neely was an internationally recognised scientist who formed collaborations and friendships across the world. His passion for his work always shone through. He always made time for early-career scientists and be...David Neely was an internationally recognised scientist who formed collaborations and friendships across the world. His passion for his work always shone through. He always made time for early-career scientists and became a mentor and supervisor to many. He was an active Editorial Board Member of the international journal High Power Laser Science and Engineering. Sadly, David was taken from us much too early. In this Editorial we pay tribute to his work through his publications in the journal.展开更多
The damage distribution of the same type of aircraft in similar service environments should be similar. Based on this assumption, to perform the maintenance and repair of aircraft composite structures, the damage of c...The damage distribution of the same type of aircraft in similar service environments should be similar. Based on this assumption, to perform the maintenance and repair of aircraft composite structures, the damage of composite structures in a certain type of aircraft were investigated. The time-varying damage distribution model was established and verified based on the damage of a 16-aircraft fleet. The results show that the quantitative proportions of structural damage are 74% for skin delamination, 22% for stringer delamination and 3% for stringer-skin interface debonding. The amount of structural damages increases linearly with service time while the proportion of different damages does not change. As the service time increases, the geometric parameter distribution of damage for the same type of aircraft gradually converges, which can be approximated using the same function. There are certain differences in the proportion and geometric parameter distribution of damages among different components and locations, and the differences do not change over time.展开更多
Myocyte enhancer factor 2B （MEF2B） gene belongs to myocyte enhancer factor 2 （MEF2） gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the...Myocyte enhancer factor 2B （MEF2B） gene belongs to myocyte enhancer factor 2 （MEF2） gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the growth of muscle, development and differentiation of nerve system and liver fibrosis. This re- view mainly focused on the structural characteristics, tissue distribution, biological functions and research progress of MEF2B gene in human and animals.展开更多
Medicine was one of the articles of tribute paid by other countries and kingdoms to the imperial court of the Qing dynasty(1644–1912).The act of paying tributes and the rituals associated with it enhanced communicati...Medicine was one of the articles of tribute paid by other countries and kingdoms to the imperial court of the Qing dynasty(1644–1912).The act of paying tributes and the rituals associated with it enhanced communication and helped establish relationships between ancient China and other nations or territories.The imperial court was generous in return,which attracted many countries to pay tributes.This paper analyzes how medicines as tributes played an important role in consolidating the dominant status of ancient China,and in promoting the exchange of knowledge between Chinese and Western medicine.展开更多
基金support from the National Natural Science Foundation of China(Nos.12372256,12072186).
文摘The noise generated by subsonic jet nozzles, commonly encountered in civilian aircraft, is rather significant and propagates in both the upstream and downstream directions due to large-scale and fine-scale turbulence structures. In this paper, a distinctive inner wall treatment strategy, denoted as the Azimuthally-distributed Wavy Inner Wall (AWIW), is proposed, which is aimed at mitigating jet noise. Within this strategy, a circumferentially dispersed treatment wall characterized by a minute wavy pattern is substituted for the smooth inner wall in proximity to the nozzle outlet. To assess the effectiveness of the AWIW treatment, we conducted numerical simulations. The unsteady flow field and far-field noise were predicted by employing Large Eddy Simulations (LES) coupled with the Ffowcs Williams and Hawkings (FW-H) integration method. To gain a comprehensive understanding of the mechanism underlying the noise reduction facilitated by the AWIW treatment, it examined physical parameters such as the Lighthill source acoustic source term, the turbulent kinetic energy acoustic source term, and the shear layer instability. The results reveal that the AWIW treatment expedites the instability within the shear layer of the jet, leading to an early disruption of the jet shear layer, and consequently turbulent structures in varying sizes are generated downstream. This process effectively regulates the generation and emission of jet noise. By controlling the minor scale turbulence through the AWIW treatment, the mid- and high-frequency noise within the distant field can be significantly reduced. In the context of the flow field, the introduction of AWIW also leads to a decrease in drag on the inner wall surface of the jet, thereby improving the overall aerodynamic performance of the nozzle. Considering these attributes, the AWIW strategy emerges as a viable technique for the reduction of jet noise.
基金supported by the Natural Science Foundation of China(Grant Nos.42030604,41875051,and 41425018)during the writing of this review。
文摘This article reviews Fuqing ZHANG’s contributions to mesoscale atmospheric science,from research to mentoring to academic service,over his 20-year career.His fundamental scientific contributions on predictability,data assimilation,and dynamics of high impact weather,especially gravity waves and tropical cyclones,are highlighted.His extremely generous efforts to efficiently transmit to the community new scientific knowledge and ideas through mentoring,interacting,workshop organizing,and reviewing are summarized.Special appreciation is given to his tremendous contributions to the development of mesoscale meteorology in China and the education of Chinese graduate students and young scientists.
文摘1.Tribute to Alfred Krner and Guowei Zhang This special issue of Geoscience Frontiers（GSF）is a tribute vol-ume honoring the life and career of two world-renowned scientists,Professor Alfred Kroner and Academician Guowei Zhang.Weassemble here a set of research papers related to continental growth in Central Asia,
基金Genetic Breeding Post Construction Project of Rice Innovation Team of Modern Agricultural Industrial Technology System of Shandong Province(SDAIT-17-01).
文摘Tangya Tribute Rice is a famous and special product in Shandong Province,and it was awarded the National Geographical Indication Certificate trademark in 2011.This paper elaborated the specific production area,unique production environment,rich cultural history and unique product quality of Tangya Tribute Rice.In addition,from the aspects of choice of origin,variety selection,production management,timely harvesting and processing,it summarized the unique production methods of Tangya Tribute Rice.Besides,it discussed its development prospects,in order to maintain the brand quality of Tangya Tribute Rice to the greatest extent,and further improve the brand awareness and market competitiveness of Tangya Tribute Rice in the domestic and international markets.
文摘It is commonly believed that most European clocks that reached China before the nineteenth century were sent to the emperor as diplomatic presents from European rulers,or were given to Chinese officials by European merchants in attempts to improve trading conditions.Although such presents had been given in earlier times,British records show that,by the eighteenth century when the export of clocks to China reached its height,most clocks,including the finest,reached China as private trade goods.Once in Canton(Guangzhou),the best clocks were bought by local Chinese officials for inclusion in their annual tribute to the emperor and senior members of the government in Beijing,where many of these clocks survive in the former imperial collection.
文摘In her article Chika Ezeanya reckons that it is an insult to the AU and to every African that a building as symbolic as the AU headquarters （HQ） is designed, built and maintained by a foreign country [China].
文摘Yongle Palace stands as a testament to ancient artistic mastery and religious devotion.lts mid-20th-century relocation highlights China's extraordinary efforts in cultural heritage preservation.
基金funded by Chinese Academy of Engineering Academy-Locality Cooperation Project(No.2019-ZJ-JS-02).
文摘Nanoemulsions(NEs)loaded with Tribute citrus essential oil(EO)were prepared using Tween-80.Five different concentrations(0,1,3,5,and 7%)were then incorporated into a gelatin base.The droplet size,PDI,and zeta potential of the NE after EO loading were found to be 241.4 nm,0.288,and-21.8 mV,respectively.The relationship between the NE and gelatin was examined by measuring the gelation behavior,water mobility,and gelatin structure.As the NE concentration increased,gel properties such as strength,hardness,springiness,adhesiveness,cohesiveness,gumminess,chewiness,and kgel declined.Gelling and melting temperatures were higher after the addition of varying amounts of NE compared with the control.Hydrogen bonding between NEs and gelatin interfered with the formation of a triple helix,as shown by multi-spectroscopic techniques including Fourier-transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD).Atomic force microscopy(AFM)revealed that higher NE contents resulted in greater aggregation in the gelatin.These results provide insight into the use of gelatin in EO delivery and describe the basic interaction between EO and gelatin and the resultant gelation behavior in the delivery system.
文摘In this paper,I trace the post-war Japanese genealogy of studies on China's tribute system(imperial China's relatively tolerant approach to its foreign relations)in relation to the English-language work of historian John King Fairbank(1907-91).I emphasize that,together with the sporadic Chinese studies into China's tribute system prior to the 1950s,it was the post-war research of Japanese historians that inspired Fairbank,who,in turn,further stimulated critical debates on the topic in Japan.I first concentrate on post-war Japanese debates concerning an"East Asian world order"based on a"system of investiture/tribute."This notion,developed by the Japanese historian Nishijima Sadao in 1962,precisely corresponds to Fairbank's 1941 understanding of the"tribute system"or"Confucian world-order,"but contrasts with Fairbank's later,controversial understanding of a"Chinese world order"as proposed in 1968.In the second part of this paper,I introduce Japanese historian Hamashita Takeshi's 1980s and 1990s arguments on the"tribute trade system"as representative of the younger generation within this genealogy,contrasting it with the work of Immanuel Wallerstein and Andre Gunder Frank.In the third part,Ⅰlocate this Japanese genealogy within the wider historical context of post-war Japanese intellectual cultural politics.This means that I examine Japanese historians'arguments both from the angle of historiography and from the perspective of post-war Japanese intellectual history.
文摘David Neely was an internationally recognised scientist who formed collaborations and friendships across the world. His passion for his work always shone through. He always made time for early-career scientists and became a mentor and supervisor to many. He was an active Editorial Board Member of the international journal High Power Laser Science and Engineering. Sadly, David was taken from us much too early. In this Editorial we pay tribute to his work through his publications in the journal.
文摘The damage distribution of the same type of aircraft in similar service environments should be similar. Based on this assumption, to perform the maintenance and repair of aircraft composite structures, the damage of composite structures in a certain type of aircraft were investigated. The time-varying damage distribution model was established and verified based on the damage of a 16-aircraft fleet. The results show that the quantitative proportions of structural damage are 74% for skin delamination, 22% for stringer delamination and 3% for stringer-skin interface debonding. The amount of structural damages increases linearly with service time while the proportion of different damages does not change. As the service time increases, the geometric parameter distribution of damage for the same type of aircraft gradually converges, which can be approximated using the same function. There are certain differences in the proportion and geometric parameter distribution of damages among different components and locations, and the differences do not change over time.
基金Supported by Financial Project from Ministry of Agriculture(2014-2130135)Specia Fund for Basal Scientific Research of Central Public-interest Scientific Institutes,Beijing Institute of Animal Husbandry and Veterinary,Chinese Academy of Agricultura Sciences(2014ywf-yb-7)~~
文摘Myocyte enhancer factor 2B （MEF2B） gene belongs to myocyte enhancer factor 2 （MEF2） gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the growth of muscle, development and differentiation of nerve system and liver fibrosis. This re- view mainly focused on the structural characteristics, tissue distribution, biological functions and research progress of MEF2B gene in human and animals.
基金This study wasfinanced by the grant from Beijing Social Science Foundation of China(No.19LSB006).
文摘Medicine was one of the articles of tribute paid by other countries and kingdoms to the imperial court of the Qing dynasty(1644–1912).The act of paying tributes and the rituals associated with it enhanced communication and helped establish relationships between ancient China and other nations or territories.The imperial court was generous in return,which attracted many countries to pay tributes.This paper analyzes how medicines as tributes played an important role in consolidating the dominant status of ancient China,and in promoting the exchange of knowledge between Chinese and Western medicine.
